The Fourth International Conference on Urban Health will facilitate an exchange of ideas about the physical and social environments of cities and health service. The conference will take place October 26-28, 2005 in Toronto, Canada. We encourage participation from anyone interested in urban health, including researchers, clinicians, community-based organizations, and government agencies, among others. Through a drug abuse track, we propose to showcase current research on substance abuse in urban environments/populations and applied aspects of NIDA's research portfolio in an effort to showcase potentially internationally applicable models of research-to-practice collaborations for urban setting. Likewise, aspects of cities are considered to contribute to mental health affects, (e.g., cities are stressful for many residents, possibly contributing to mental illness), yet cities offer many support services and social structures that can be preventive or therapeutic for mental illness. As such, we are requesting approximately $60,000 to fund the following drug abuse and mental health research components of the program: 1) Plenary speakers on drug abuse and mental health research 2) Concurrent sessions on drug abuse and mental health research 3) Poster sessions focused on drug abuse and mental health research 4) Publication of special Journal of Urban Health that will include featured articles and poster abstracts on drug abuse and mental health research The goal of the conference is to foster an international research group to collectively improve the understanding of the common health risks faced by urban residents, and to influence the development of effective public health interventions across the globe. We have now held three prior conferences that have been well attended and look forward to continuing this series. The tracks on drug abuse and mental health have been present in earlier meetings and are critical parts of this effort. These tracks will help to foster interdisciplinary collaborations among researchers in each of these areas among attendees who are interested in how urban settings play a role in drug abuse and impact mental health and how features of urban settings may lend themselves to interventions.